I used ground beef for a cottage pie. I added about a cup of heavy cream to the cauliflower mixture when whipping it because it was too dry. I initially tried using a hand mixer which was not strong enough and then switched to my blender which was way too aggressive. The food processor is probably the way to go, unfortunately mine died recently. As far as taste, it was terrific! I didn't miss the peas at all and the mashed cauliflower was amazing.
Used Bob's Red Mill blanched almond flour and subbed in pepitas (pumpkin seeds) and shelled hemp seeds. Also the bake time is closer to an hour. My cake tester comes out clean after 30 minutes but the outside will still appear underdone, and it will be.
So good, I substitute blue cheese crumbles for the cheddar cheese and add about half a teaspoon of xanthan powder to a tablespoon of olive oil and melted butter to make a slurry which I add just before I add the cream to make it thicker.